This project will develop a complete, practical, cost effective high density electro- physiology recording system for general neuroscience and biological neural network research. This project involves design of: 1) small, lightweight, on-animal electronics; 2) computer interfaces; and 3) software for storing acquired data, experiment control and data analysis. Biological neural network research involves spontaneous investigation of large ensembles of neurons and requires data acquisition and storage on a large number of recording channels to construct the time firing sequences of neuronal assemblies. The goal is to reconstruct the population state- vectors of neural systems involved in sensory motor integration and cognitive processing, specifically in conscious, freely behaving animals. Recent success in electrode and manipulator technology has made possible simultaneous recording from over 100 CNS neurons (Wilson & McNaughton, 1993). The data acquisition system used in those studies was designed by the P.I. working in collaboration with Drs. Wilson and McNaughton. This design, while very successful, has encountered new practical limitations: cable harness mass, rotatable harness commutator, system manageability and cost. The proposed system will employ new electronic and computer technologies to overcome current constraints on channel density and provide the next generation tools for biological neural network research. PROPOSED COMMERCIAL APPLICATION: The system will be marketed to neuroscience researchers at universities and institutions involved in neuroscience research.